Contact blade assembly for relays



April 22, 1969 A. T. ELLIS, JR 3,440,584

CONTACT BLADE ASSEMBLY FOR RELAYS Filed Jan. 1o, 19e? f THE f who: Afro/Pigs? y April 22, 1969 A. T. ELLIS, JR

CONTACT BLADE ASSEMBLY FOR RELAYS Sheet File'd Jain. lO, 1967 hr2/M United States Patent O ILS. Cl. 335-19 10 Claims ABSTRACT OF THE DISCLOSURE A contact blade assembly for an electric relay having a wedge shaped insulator providing an angular mounting surface for one of the contact blades to increase the area of the contacts of the blades in actual engagement with each other during operation of the blades of the relay.

Background of #reinvention Electromagnetic relays having more than one set of vertical contacts have generally relied upon the biasing of an intermediate contact blade toward an upper contact blade to obtain electrical engagement between the contact surfaces of the intermediate and upper contact blades. Such electrical engagement has not been satisfactory due primarily to the angular juxtaposition of the contact surfaces when meeting. Heretofore, each of the contact blades have been mounted one above the other in parallel relationship. The intermediate contact blade bends and tends to move in an arc as it is pressed toward the upper contact blade. Such radial movement hasresulted in a very limited engagement area between the surfaces of the contacts when they meet as the faces of the contact surfaces are in angular relationship, As a result, there tends to be arcing between the contact faces with resulting pitting of the contact surfaces and increased electrical resistance.

Brief summary of invention It is an object of my invention to provide a means for increasing the contact area between matching contact surfaces without increasing the size of such contacts.

It is a further object of my invention to improve the operation of the relay contacts by providing for more efficient electrical contact and more eicient operation.

It is a further object of my invention to provide blades so positioned with reference to each other that minimum pitting of the contact surfaces and voltage losses will result at the contact meeting surfaces of such blades.

It is a still further object of my invention to have all contact surfaces substantially parallel with each other when they are in engagement with each other.

The foregoing and other objects of this invention, the principles of this invention, and the best modes in which I have contemplated applying such principles will more fully appear from the following description and accompanying drawings in illustration thereof.

In the drawings:

FIG. 1 is a side elevational view of an electromagnetic relay made in accordance with the invention;

FIG. 2 is a top plan view of the relay illustrated in FIG. l;

FIG. 3 is a front elevational View of the relay illustrated in FIG. l;

FIG. 4 is a rear elevational view of the relay illustrated in FIG. l;

FIG. 5 is an exploded, perspective view of the contact blade assembly of the relay showing but one vertical set of contact blades;

FIG. 6 is a side elevational view, partly in cross section, of the stack assembly of the relay showing engagement of the contacts of the upper blades; and

3,440,584 Patented Apr. 22, 1969 FIGS. 7, 8, 9 and 10 are side elevational views of modilied stack assemblies for the relay illustrated in the preceding figures of this invention.

Referring to the drawings, FIG. l illustrates an electromagnetic relay 10 comprising a generally L-shaped frame 12, a solenoid coil 18 and an armature 32 having a generally horizontal leg 35 on which is mounted an actuator arm 34 (by rivets or the like) for actuating the contact blades 56, the generally horizontal leg 35 and actuator arm 34 being at approximately a right angle to a generally vertical leg 33 of the armature 32, as shown.

The L-shaped frame 12 has a vertical leg 14 through which extends a tube 16 of nonmagnetic material and about which is mounted an electromagnetic solenoid coil 18 on the right hand portion of the tube 16, as seen in FIG. 1. On the horizontal leg 20 of the frame 12 is mounted a contact blade assembly 22 which is secured to the horizontal leg 20 by means of rivets 24. Side brackets 25 extending from the frame 12 permit the relay to be secured to a surface by means of the tabs 27.

A pair of ears 26 project upwardly from the horizontal leg 20 and such ears 26 have openings 28 to carry a pin 30 on which the armature 32 and the actuator arm 34 are pivoted. The pin 30 also extends through upstanding ears 36 formed integral with the armature 32. A coil spring 38 is tightly wrapped about one end of the pin 30 and the end portions of such spring 38 are hooked about opposite sides of the adjacent ear 26 so as to restrain rotation and axial movement of the pin 30. The other end portion of the pin 30 carries a torsion coil spring 40 which biases the armature 32 away from the pole face 42 of the solenoid coil 18. One end of the spring 40 is hooked through the hole 44 in the actuator arm 34 while the other end is caught in the notch 46 on the end of the pin 30. The tension of the spring 40 may be adjusted as desired by inserting a tool in the notch 46 and rotating the pin 30.

The contact blade assembly 22 comprises an insulating base 50 with a pair of insulating bosses 51 (see FIG. 5) on which is stacked, in vertical sequence, a contact blade 52, an insulating spacer 54, a second contact blade 56, an insulating wedge spacer 58, a third contact blade 60, a second insulating wedge 62 and a holding member 64, the assemblage being tightly secured together by threaded bolts 66 extending through a threaded plate 68. The metal contact blades 52, 56 and 60 are electrically conductive land have terminals 70, 72 and 74 at the rear of said stack. At the other end of the blades from the terminals are mounted contact buttons.

The iirst contact blade 52 has a contact button 76 on its upper face which is normally engaged by the lower contact button 78 secured to the lower face of the second contact blade 56. The second contact blade 56, which is generally parallel to the first contact blade 52, also has an upper contact button which is normally spaced from the contact button 82 depending from the lower face of the blade 60.

As may be seen in FIGS. 1 and 6, in normal position the substantially at faces of the contact buttons 76 and 78 are approximately parallel to each other and are in engagement with each other whereas the faces of the contact buttons 80 and 82 are spaced apart and are inclined with respect to each other. However, when the armature leg 33 is pulled toward the pole face 42 by the energization of the solenoid coil 18 and the actuator 34 is moved clockwise (as viewed in FIG. 1) so as to engage the finger 84 on the tip of the blade 56 and push the blade 56 counterclockwise until the fa-ce of the contact button 80 engages the face of the contact button 82 then such faces are substantially parallel to each other (FIG. 6). At such moment, the faces of the contact butto-ns 76 and 78 are spaced apart and are inclined with respect to each other. Upon deenergization of the coil 18, the actuator 34 returns to initial position whereupon the spring-like blade 56 returns to the position shown in FIG. l and the faces of the contact buttons 80 and 82 are once again spaced and the faces of the contact buttons 76 and 78 are once -again in engagement with each other.

Preferably the wedge shaped insulator spacers 58 and 62 are equal segments so that one can be substituted for the other merely by reversing the piece. The preferred angle of the wedge 58 depends primarily upon the angle that the face of the contact button 80 will assume when it is rotated into position by the liexing of the blade 56 under pressure of the actuator arm 34 secured to the armature 32. The greater the angular movement of the blade 56 and finger 84 to engagement position, the greater Will be the angle of inclination of the Wedge. ln any event the angle of the wedge should be such that upon engagement of the faces of the contact buttons 80 and 82 the faces will be substantially parallel so that the maximum amount of face area will be in contact thereby substantially eliminating any tendency to arc. Heretofore, when horizontal blades were used the engagement of the contact buttons took place at that portion of the face of the movable contact which was closest to the finger of the blade: the remainder of the face of the moveable contact was angled away from the opposite face thereby producing arcing conditions.

It is preferable to bend the rear end (left hand slide of FIG. l) of blade 60 upwardly so as to space the terminals 72 and 74 of the blades 56 and 60.

Cavities 90 are preferably provided in the base 50 into which the contact blade 52 may be depressed. While the contact blade 52 is substantially stationary the normal pressure between the contact buttons 76 and 78 may be such as to slightly bias the blade into the cavity 90. When the intermediate blade 56 is pressed upwardly toward the upper blade 60 the first contact blade 52 will move out of the cavity 90 into a horizontal plane. Such slight movement of the lower blade 52 combined with the movement of the intermediate blade `56 will provide some wiping action between the faces of the contact buttons '76 and 78.

FIGURES 7, 8, 9 and 10 illustrate modifications of the means for presenting a contact blade angularly spaced from a moveable contact blade.

In FIG. 7 there is illustrated a double angle wedge 100 which angularly spaces the contact blade 102 not only from blade 104 but also the terminal 106 from the adjacent terminal 108. Such spacing eliminates the possibility of engagement between the terminals. In FIG. 8 a notch 110 is provided in the rear of the wedge 112 to increase electrical resistance between the terminals 114 and 116. In the modification shown in FIG. 9 a piece of insulating material 120 projects beyond the rear wall of the wedge to provide increased electrical resistance between the terminals 122 and 124. In FIG. l0 there is illustrated a modification in which a larger Wedge 126 is used to permit a greater travel of the contact blade 128 prior to engagement of the contact buttons.

Having described this invention, what is claimed is:

1. In a device of the character described, the com-bination of a magnetizable frame, a solenoid carried by said frame, an armature and an `arm joined together and pivotally mounted on said frame and actuated by said solenoid coil, a contact blade assembly mounted on said frame comprising a base of insulating material, a first contact blade supported on said base, a spacer of insulating material biasing said contact blade toward said base, a second contact blade mounted upon said spacer, a first wedge shaped insulator biasing said second contact blade against said spacer, a third contact blade mounted upon said wedge shaped insulator so that the second and third contact blades form an angle diverging away from each other, and a second wedge shaped insulator biasing the third contact blade against said first wedge shaped spacer,

and means clamping said spacer, blades, insulators, and base together, said arm when actuated engaging said second contact blade and moving it into engagement with said third contact blade.

2. The structure recited in claim 1 wherein said contact blades carry contact buttons having substantially flat faces, said second contact blade having a contact button on either side of said blade and the first and third contact blades having contact buttons facing the second contact blade.

3. The structure recited in claimI 2 wherein the faces of said contact buttons are substantially parallel to each other when in engagement with each other.

4. The structure recited in claim 3 wherein said second contact blade has a finger at its end remote from said wedge shaped insulators, said armature engaging said finger and actuating said second contact blade.

5. The structure recited in claim 3 wherein one of the contact buttons of said second contact blade is normally biased into engagement with the contact button on said first conta-ct blade.

6. The structure recited in claim 1 wherein said base includes an upstanding integral boss, said boss having a noncircular outer shape, and said spacer, blades and wedge shaped insulators having mating noncircular holes through which said 4boss extends.

7. A contact blade assembly for an electric relay comprising a base of insulating material, a first contact blade resting upon said base, a spacer of insulating material upon said first contact blade, a second Contact blade upon said spacer, a wedge shaped insulator upon said second contact blade, a third contact blade mounted upon said wedge Shaped insulator, said second and third contact blades extending outwardly from said wedge shaped insulator at the approximate diverging angle of the wedge, said Contact blades having raised contact buttons, and means securing said base, spacer, wedge shaped insulator, and contact blades together, and further means inclining an end portion of said second contact blade parallel to an end portion of said third contact blade.

8. The structure recited in claim 7 wherein said first mentioned means includes a boss integral with said base, said boss having an angular outer surface, said spacer, wedge shaped insulator and contact blades being juxtapositioned by said boss which extends into mating angular openings in said spacer, insulator and blades.

9. A contact blade assembly for an electric relay comprising a wedge shaped insulator mounted on said relay, said wedge shaped insulator providing an angular mounting surface, a flexible movable contact blade mounted on said angular mounting surface of said wedge shaped irlsulator and extending therefrom at the approximate angle of the Wedge, and a second relatively nonmovable contact blade mounted upon the other side of said wedge shaped insulator, said contact blades being relatively at and having engageable end portions, whereby the contact blades are mounted at an angle to each other, and said movable contact blade being exible and movable toward the angle of said relatively nonmovable contact blade, said wedge shaped insulator being positioned between said contact blades, whereby upon flexing movement of the movable contact blade toward engagement with the nonmovable contact blade a substantially parallel mating of said engageable portions occurs.

10. A contact blade assembly for a relay comprising a base of insulating material, a substantially horizontally mounted at contact vblade mounted on said base and having a substantially flat faced raised contact button at the end opposite from which it is mounted, a second substantially flat contact blade having a substantially flat faced raised contact button spaced from but engagable with the contact button of said first contact blade, means between said first and second contact blades mounting said second contact blade on said base at an angle relative to said first contact blade, a third substantially flat contact blade having a substantially flat faced raised contact button at the end opposite from which it is mounted, said means including a member between said rst and third blades mounting said third blade substantially parallel to said first blade, said raised contact button of said rst blade being movable from a position where it engages said raised Contact button of said third blade across substantially their full faces to a position where said raised contact button of said first blade engages said raised contact button of said second blade across substantially their full faces when said iirst contact blade is flexed to an angle approaching that of said second contact blade.

References Cited 6/1947 Wood 20o-165 15 6 2,458,518 1'/ 1949 Kohl. 2,597,083 5/1952 Hood 20G-166.1 2,663,770 12/1953 Cox. 2,690,526 9/1954 Morrison 200-1661 FOREIGN PATENTS 971,859 3/1959` Germany.

BERNARD A. GILHEANY, Primary Examiner.

10 H. BROOME, Assistant Examiner.

U.S. Cl. X.R. 200-166 

